The present invention relates, generally, to a bywire system shift lever device for vehicles and, more specifically, to a bywire system shift lever device suitable for automatic vehicles.
Hitherto, the shift lever device for automatic vehicles includes a transmission switching unit utilizing a mechanical link mechanism. However, in order to cope with demand for computerization of vehicle-mounted equipment, a bywire system transmission switching unit has been developed in which the switching position of the shift lever is detected by a position sensor. An actuator such as a solenoid and a motor is driven in accordance with output signals from the position sensor to drive a transmission switching fork is proposed.
The shift lever device for automatic vehicles also requires a sensory resistance mechanism for providing an adequate sensory resistance to the shift lever when the shift lever is moved from one shift position (for example, the drive position: D) to another shift position (for example, the neutral position: N) in order to ensure good operability of the shift lever.
The bywire system shift lever device for vehicles of the prior art is provided with the sensory resistance mechanism described above. However, there is such disadvantage that when the sensory resistance mechanism has a problem, such sensory resistance mechanism tends to be locked in position so that a change of the shift position by the shift lever is disabled. In addition, the complex construction of the sensory resistance mechanism results in upsizing of the sensory resistance mechanism.
In shift lever devices for automatic vehicles having a bywire system transmission switching unit, it is not necessary to provide a large sized and complex link mechanism between the driver""s seat and the engine room, and what have to be done is just to distribute several pieces of electric wires, whereby flexibility of design of the vehicle may be significantly increased.
In order to solve the problem described above, an object of the bywire system shift lever device for vehicles according to the present invention is to provide a compact bywire system shift lever device for vehicles, in which reliable change gear operation is achieved.
The bywire system shift lever device for vehicles according to the present invention includes: a base member; a lever member mounted on the base member so as to be capable of being driven within a predetermined range of angles and having an operating element; the lever member being driven by operating the operating element; an electric motor mounted on the lever member; a transmission mechanism for transmitting rotation of a rotating shaft of the electric motor to the lever member; a first position detecting sensor for supplying first position signals representing the operating angle of the lever member; and a second position detecting sensor for supplying second position signals representing the operation of the lever member via the transmission mechanism, and a rotational force of the rotating shaft of the electric motor is controlled by the second position signals so that a predetermined sensory resistance is provided to the operating element by a force of the rotating shaft of the electric motor applied via the transmission mechanism.
In this arrangement, since the sensory resistance providing mechanism is constructed of the electric motor and the transmission mechanism for transmitting the rotation of the rotating shaft of the electric motor to the lever member, the structure is simplified, and thus the compact shift lever device for vehicles may be provided.
In the bywire system shift lever device for vehicles according to the present invention, the transmission mechanism includes: a wire the both ends of which are attached to the base member; and a pulley secured to the rotating shaft of the electric motor, and the wire is wound around the pulley between both ends thereof, the winding position of the wire wound around the pulley is moved while rotating the pulley by the operation of the lever member, and the rotating shaft of the electric motor is rotated in the direction opposite from the direction of rotation of the pulley, so that a predetermined sensory resistance is provided to the operating element.
In this arrangement, since the construction of the transmission mechanism is such that the wire is simply wound around the pulley, the pulley can be moved as if the wire slides over the outer peripheral surface of the pulley in some cases. Therefore, even when the rotating shaft of the electric motor cannot be rotated due to a defect thereof, the first position signals representing the operating angle of the lever member may be supplied from the first position detecting sensor by moving the lever member and thus the reliable operation of the lever member is achieved.
The bywire system shift lever device for vehicles according to the invention is characterized in that a supporting unit having a semi-circular sliding surface, the diameter of which is larger than the diameter of the pulley, is provided on the base member, in that the outer peripheral surface of the pulley and the sliding surface of the supporting unit are faced toward each other, and in that the wire is positioned along the sliding surface of the supporting unit so that the winding position of the wire on the pulley moves along the sliding surface.
In this arrangement, since a speed reducing mechanism is constructed by the pulley, which is smaller in diameter, and the sliding surface, which is larger in diameter, a small electric motor having small rotational torque may be arranged and thus a compact bywire system shift lever device for vehicles being blessed with stable operation may be provided at a low cost.
The bywire system shift lever device according to the present invention is characterized in that a spring member is attached at one of the ends of the wire, and the spring member is provided with an adjusting member for adjusting the tensility thereof.
In this arrangement, the tensility of the wire may be adjusted to a predetermined force easily by the adjusting member attached to the spring member, and thus a predetermined stable sensory resistance may be achieved.
The bywire system shift lever device for vehicles according to the invention is characterized in that the electric motor is disposed on the side of the operating element of the lever member, and the first position detecting sensor is disposed within the moving range of the lever member on the base member on the fulcrum side of the lever member.
In this arrangement, the device may be downsized, and the position of the lever member within the predetermined angular range may be reliably detected by the first position detecting sensor.
The bywire system shift lever device for vehicles according to the present invention is characterized in that the first position detecting sensor is constructed of a potentiometer, and the second position detecting sensor is constructed of an encoder.
Since the potentiometer and the encoder are low in price, the cost-effective bywire system shift lever device for vehicles may be provided.
The bywire system shift lever device for vehicles according to the present invention is characterized in that the wire wound around the pulley moves as if it slides over the outer peripheral surface of the pulley by operating the operating element when the transmission mechanism fails to be driven or when the electric motor fails to be rotated, so that the lever member can actuate the first position detecting sensor, and thus the electric motor can be controlled by the first position signals from the first position detecting sensor.
In this arrangement, the bywire system shift lever device for vehicles in which the position of the shift lever can be reliably detected within a predetermined angular range by the first position detecting sensor even when the transmission mechanism or the electric motor has a problem, which may occur on occasion.